LiFePO4 battery experiences and adventures! Power Queen and GoKWh

rruff

Explorer
Summary: Test your batteries! One of these performed like it should and the other did not. If you buy from Amazon or a similar retailer (a good idea!), you typically have 30 days to return it. I also suspect that many of these batteries are defective out of the box, and that the glowing reviews don't mean much, since it's very rare that they are tested. Even the numerous youtube reviews do not test the balancing function of the BMS, which is the issue I had with the Power Queen. We need to make sure that an item with a purported 10 year life is at least functioning properly when new!

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The long and rambling version...

I originally was planning to buy individual cells, busbars, and BMS, build a box, etc... just because this is how I normally do things. But lately I've been weary of the time and effort required to custom build thousands of little things, and based on the reviews I've seen, it seemed that the inexpensive Chinese LiFePO4 batteries had been sorted out pretty well, so why not go the easier route?

After some investigation I settled on either LiTime (formerly Ampere-time) or Power Queen. These are both made by the same company, have had US warehouses for awhile, are sold by Amazon, and have good reviews... typically 4.6-4.7 on average. The best deal I thought was a PQ 100Ah 12V "trolling motor" battery that has low temperature cutoff. Another slight bonus was higher short term amperage... figured I could probably crank my truck with it if necessary, if I had a pair of them. The plan was to buy one and get another if the first one worked out. It was ~$220 plus tax, purchased in late Nov 2023. Another nice aspect is that if you buy from Amazon late in the year, you have until Jan 31 to file a return, allowing more time to evaluate.


I didn't see any formal reviews of this battery, but there were several of the LiTime model which is made by the same factory and has the same specs.

 
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rruff

Explorer
Oddly, I got a message a few days later from Steve at Lightning-Energy, wanting to give me a free battery of the same size, a GoKWh brand with the stipulation that I post about my experiences with it online. I like free stuff, and have a couple forums I post on regularly, so why not? I figured that this would be my 2nd battery and I'd forget about an additional PQ. I discovered that at least 3 reviewers found a JDB BMS (top brand) with low temp cutoff on this battery, so mine probably has it as well, though it isn't listed as a feature. I was planning to take a camping trip for a couple weeks (delayed to early Jan) and I was scrambling to get my new camper build set up for its maiden voyage. I was hoping to have both batteries, the charge controller, and the wiring set up in time.


(this guy discovered that it had a JDB BMS with low temp cutoff)

(this guy as well)

(this guy found that the low temp cutoff worked, but was set too low... not good!)

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The GoKwh battery has been drama free. It took a few weeks to arrive, but as it turned out this was soon enough for me to use it on my trip. When I tested it, the capacity was 104.1Ah, and the voltage went up to near 15.0V (>14.9V anyway) before the BMS cut off charging, indicating that the cells were balanced and the BMS was likely doing its job. IMO the most outstanding feature of this battery is that it can be taken apart! Some of the youtube videos show this; there are plugs on top that cover screws. If you take the screws out, the top comes off allowing access to the innards. I guess most people wouldn't care about this, but I was really wishing the PQ battery had this feature! Then I could have poked around with a multi-meter and found out what was really going on. Note that doing this without company permission would surely void your warranty, so it's only relevant if there is already a problem.

The company info as well as reviews show that this battery has pouch cells rather than prismatic. I spent some time researching online to see if there was a consensus regarding which was better... and there doesn't seem to be any. Pouch cells are being used a lot now, at least in the less expensive batteries, and they should last as well as the prismatic ones in a similar price range.

This battery has a voltage meter with an LCD display on top that you can kinda use as a capacity meter. Checking capacity with voltage is very crude with LiFePO4 though, plus this meter only displays to the nearest 0.1V. I have a better monitor that measures actual energy in and out, plus when it's mounted in the camper I can't see the battery display, so I didn't attempt to use this feature on the battery.

One thing some youtube reviewers complained about was soft (rather than firm) foam inside the case. I didn't take mine apart, but I did shake it to see if I could feel anything shifting around, and did not. I will take it apart later and check out the insides, but I'm planning another trip, and need to use it, since now it's the only one I have.

Wait, I just had another look at the latest youtube reviews and they are certainly sending out a lot of free batteries! They have a US warehouse now, have a battery display that is hooked up to the BMS that shows important info (unlike the old one), and they have Bluetooth. They are using firm foam inside the battery case now as well. Here is a good review of the upgraded version. The downside is that the BMS low temp cutoff is still too low, something this reviewer noted on the previous model. He mentions the high and low voltage cutoffs being too far out as well, but that doesn't bother me since the BMS is only the last layer of protection; you will set these at appropriate values using your charge controller. For most people the cells will only have low temperature protection from the BMS though, and this is also the best place to provide it, since the probe is inside the case. They'll probably fix that issue in the next iteration.


Even though my experience so far with the GoKWh battery has been positive so far, this is what I'd expect from any company... at least 95%, maybe 99% of the time? The customer should not serve as the QC department. However, my experience with Power Queen left me wondering if many of these batteries are defective, and the consumers simply don't realize it... at least not initially.

The GoKWh battery clears that hurdle in my n=1 experience. If they sell on Amazon for awhile at least, build a good rep, and establish themselves in this market, I think they will make it. But... if I was a random person purchasing a battery from GoKwh and had an issue like I did with the PQ battery, I don't know what they would have done. Would they have admitted it was defective and replaced it free of charge, with free shipping, or issued a full refund? Or would they have given me the run around like PQ? The rate in which they are modifying and improving their batteries over the last 2 months shows that they are responsive to reviewer feedback and are making a serious effort, so I'm hopeful that they will have the same attention to customer service.

Features on the new model with BT, low temp cutoff, and accessible case are pretty ideal for overland use... once they get the low temp setting fixed. Well, I guess they could make them smaller and lighter too, that's always nice! One thing that would be useful at an affordable price is self-heating. This is starting to become more mainstream. If the battery is below freezing and a charging input is sensed, the current will be diverted to heating pads until the cells are brought above freezing temperature, and then charging will commence. This allows a person to charge their batteries even if it's well below freezing. Not something I expect to need, but a good feature for people who winter camp and do not have their batteries in a heated space.
 
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rruff

Explorer
My experience with the Power Queen battery was not so simple. I used a little hobby charger I've had for a few years to charge it. I discovered this would only charge at ~4A so it was a slow process. To discharge I hooked the battery up to a small 12V-110AC inverter, a Kill-A-Watt, and a 250W heat lamp. I knew this would be a crude measure of discharge energy since the inverter efficiency is unknown, but I thought the charger's measure of input energy would be accurate. Unfortunately, that wasn't true! After a full discharge, the charger showed 116Ah to fill it. There is no way a 100Ah battery would have that much extra capacity, so I knew a real test would need to wait until my battery meter with shunt arrived.


One odd thing I noticed though, was that the battery would shut off charging at ~14.0V, while I expected more like 15.0V. BMS's have a function to shut off charging if a cell voltage gets too high. This is safety function and is typically ~3.75V per cell. Note that these batteries have 4 cells in series. I got the manual out and saw that PQ recommends setting the charge controller to 14.4V +-.2V, and you never want the BMS to cut out before the charge controller... so something wasn't right. I posted on the DIY Solar Power Forum, and was advised to set it to charge at a fixed voltage that was just under the point where the BMS trips. This would hopefully activate the BMS balance function. My charger wouldn't allow setting a voltage, but I repeatedly charged the battery in the 13.7-14.0 range at 0.1A, so that it accumulated at least a couple hours in this range, with no improvement.


Once my meter arrived I was able to do a good capacity test, and that was fine... 106Ah! Actually that is a bit extreme for a 100Ah battery which made me wonder if it had 100Ah cells, or cells of a higher capacity that were degraded or rejects. At any rate despite the high capacity, if one or more of the cells are out of balance, and the BMS doesn't fix this, it is likely to get worse. And it's in a sealed box so I can't balance it myself. For a battery that is supposed to last 10 years, this isn't good.


I got the solar charge controller (Epever Tracer), the battery monitor (Qwork), and associated wiring, circuit breakers, and fuses installed in the camper, and connected the PQ battery in parallel with the GoKWh. After a brief check at home, I took a 2 week camping trip to Big Bend and the Terlingua TX area. The plan where the PQ battery was concerned, was to set the max charge to 13.9V and "boost" charge to 13.8V (for 180 minutes, the longest setting). Since I had plenty of solar for the energy I was using (mostly a laptop), this gave me 3 hours per day of holding the battery just below the point where the BMS was shutting off the charge. If the BMS was ever going to balance the cells, this should do it.


But... when I got home from that trip I tested the PQ battery again and the BMS was shutting off at 13.9V now rather than 14.0V. Getting worse. So I contacted PQ to see what they said. Their standard questions when there is a problem are "what charge controller do you use?" and "what is the settled voltage of the battery after charging?"... which is the voltage after you let it sit for an hour or so. Neither of these was relevant to my issue, but I gave them the info, and then they asked for a video of the behavior, which I supplied. I also asked them if the BMS even has a balancing function, and if so what are the parameters for it to balance the cells?... details of its operation. I was still trying to come up with a way to fix it, rather than send it back, or at least understand what was wrong. The first two times I asked the question I was ignored, but finally I got a reply that they would not tell me how the BMS operated, except to say that it cuts off charging if one of the cells exceeds 3.65V. If all 4 cells were in perfect balance this adds up to 14.6V. Since the BMS is a protection mechanism, and their own manual recommends setting the charge controller as high 14.6V, and you never want the BMS to terminate while the charge controller is functioning... I doubt it's that low. 3.75V or so is typical, or 15.0V for a perfectly balanced 4 cell battery. Anyway, I'm not getting close to 14.6V, and the situation is worsening despite doing everything I can think of to help it. Meanwhile they kept telling me that if the battery settles to 13.3V or more then it's totally fine, fully charged, no worries. This is also not true. You can look up LiFePO4 battery voltage vs charge level and all the charts will show you that the curve is very flat, and also that 13.3V for a 4 cell battery is probably in the 80-90% range for charge level. I didn't mention that I was able to get 106Ah out of it prior to the trip (I didn't test it after). But that's irrelevant IMO. The battery is supposed to last for 10 years and many thousands of charge cycles and if the BMS balancing function doesn't work, the odds of that happening are nil.


I started the return process through Amazon on the last possible day. There was some weirdness with that also, as the return label came from PQ directly, and they told me not to use an Amazon label as "Amazon would charge me too much". The label they sent said "postage due", and I thought the return shipping should be free for defective merchandise. More emails with PQ. They eventually agreed to send me a prepaid label, but they never agreed that the battery was defective, maintaining throughout that it was fine. They also said that they were going to replace it, rather than refund my money. I twice told them that I wanted a refund, not a replacement since if the new battery behaved in the same way, it would also be returned. Also when I initially requested the return with Amazon, a refund to my CC was the listed resolution, not a replacement. I was confused about what was going on and still am, but a day after I shipped the battery I got an email from Amazon stating that my original CC charge had been refunded. A day later I got an email from PQ stating the same.


I took a closer look at all the reviews on Amazon and discovered that nobody really tests them. One person actually bragged that the voltage went to 13.9V... not realizing that it should have gone to ~15.0 before shutting off. "It works!" is about all you can glean from the positive reviews, and the negative ones are mostly total failures. Also because different varieties of batteries are sold from the same page, and the Trolling model was fairly new, there were few reviews of it, and no indication that it was actually tested. There are youtube reviews of the LiTime version of the same battery, but they did not check the maximum voltage or balance of the cells.


Based on my experience with Power Queen, and their repeated insistence that the battery was fine even though it clearly wasn't, I think that the "5 year warranty" they state is not worth much. If I'd bought from them directly, I'm pretty certain they wouldn't have taken it back. At some point down the road if the battery completely died in under 5 years, they may have given me a prorated replacement with shipping at my expense. They have US warehouses, have been in business a couple years, have mostly great Amazon reviews, as well as good youtube reviews, and still... your best warranty is with Amazon, and it typically lasts for only 30 days.

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The moral of this story is to have the means on hand to test your battery as soon as you get it! I think most of us will have a battery monitor, and all of us should have a solar charge controller. I you lack a monitor you can drain it until the BMS cuts off, then hook it up to solar and charge it (with no loads!) until the BMS cuts off charging again. Be sure to set the controller limits high enough so this happens. Note the Whrs or Ahrs it took and compare to specs, and also check that the battery achieved spec voltage (at least 3.65V per cell). If you have to watch it to find the cutoff point (like me!), then let it fully charge and settle for a while, or give it a brief load to reset the BMS disconnect, and charge it again. It will take very little for it to max out this time because it's already full. If these tests results are fine then at least you know the cells are balanced and the capacity is alright, and BMS is probably working correctly at the start.

If you have low temp protection and you plan to use it, it's good to test that as well... but it isn't easy especially if you can't take the battery apart. BT is helpful in that case, because at least the settings are shown. Otherwise you need to stick it in the freezer... but not at 0F, rather at something in the high 20s at least, and let it saturate. Since the only freezer I have is the one in my house, and I keep food at 0F, that one would be tough...

Or you roll the dice and hope for the best... or go with a company that really stands behind their product, and will guarantee to replace the battery completely free of charge or shipping costs, for any defect, for at least 1 year... better 2. Are there any of those?
 
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Dave in AZ

Active member
Thank gosh you provided a TLDR!!
I will save this for when I am stuck somewhere waiting for 30 min lol. I browsed and looks like some good info... going out to try draining my new 100Ah redodo mini into my power station to check capacity...
 

rruff

Explorer
I do apologize for the length. It looked a lot smaller in my text editing program... Now you might have some idea why I've never made a build thread... my part alone would have been 100+ pages, and that still would have just scratched the surface... :ROFLMAO:

Good luck with testing. It isn't fun but I feel like the people who are able to do this kinda need to, to keep the companies honest, so they provide good products and service.
 

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